Case study · Custom
A floating stair clad in porcelain
Seventeen treads, a double-height feature wall and a landing, all in 12mm large-format porcelain with mitered nosings.
Custom, Arlington, Virginia
2026
Large-format porcelain, 12mm, marble-look, matte
- Material
- Large-format porcelain, 12mm, marble-look, matte
- Scope
- Stair treads and risers, double-height feature wall, landing
- Timeline
- 4 weeks in two phases
- Team
- Architect, steel fabricator, general contractor, Prime Stone Design
01
The request
The architect designed an open steel stair floating in front of a double-height wall. Stone would have been too heavy for the cantilevered treads, and the wall panels were taller than any slab of natural stone. The answer was large-format porcelain: thin, light, hard and available in sheets up to 126 inches.
The brief asked for the same material on every surface, the pattern to run continuously up the wall, and no visible porcelain edge anywhere.
02
The challenge
Porcelain slabs are printed, so the pattern sits on the surface and a cut edge shows the plain body. Every exposed edge, including the nosing of all seventeen treads, had to be mitered and glued so the pattern wrapped the corner.
The steel stair was fabricated to tolerance, not to the millimetre: each tread was a slightly different length, and the wall panels had to be installed in a stairwell with no room for a lift.
The stairwell during installation
Steel stair, treads numbered
Wall panels up to 126 inches
03
How we solved it
- 01
Scan the whole stairwell
We laser-scanned the finished steel stair and the wall as a single model. Every tread was measured and numbered individually, and the wall was divided into panels that followed the pattern of the slabs.
- 02
Dedicated porcelain programmes
Porcelain needs different blades, feeds and handling than stone. Each tread and riser was cut on our porcelain CNC programme, with 45-degree miters on every exposed edge, and assembled into L-shaped pieces in the shop so the nosing reads as solid material.
- 03
Install in sequence, bottom to top
Treads went in from the bottom up on a flexible adhesive so the steel can move slightly without cracking the porcelain. The wall panels were carried in by hand and set with the pattern continuous from floor to ceiling.
Before and after
Same room, two moments.
Drag to compare the stairwell mid-installation and finished.
04
The result
The stair and the wall read as one material. The pattern runs continuously up the double-height wall and every nosing looks like a solid block, with no porcelain body visible anywhere.
At 12mm the cladding added almost nothing to the load on the steel, and the surface is heat-proof, scratch-resistant and needs nothing more than a damp cloth.
17
treads, each cut to its own length
126"
tallest wall panel
12mm
material thickness
The finished work
“We had been told the stair could not be clad in one material. Prime Stone treated it as a fabrication problem and solved it.”
Materials and details
- Large-format porcelain, 12mm, matte
- Mitered nosings on all treads
- Double-height wall panels, pattern-continuous
- Flexible adhesive on steel substrate
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